Rename map_entities and map_specific_entities (#7570)

# Objective

After fixing dynamic scene to only map specific entities, we want
map_entities to default to the less error prone behavior and have the
previous behavior renamed to "map_all_entities." As this is a breaking
change, it could not be pushed out with the bug fix.

## Solution

Simple rename and refactor.

## Changelog

### Changed
- `map_entities` now accepts a list of entities to apply to, with
`map_all_entities` retaining previous behavior of applying to all
entities in the map.

## Migration Guide 

- In `bevy_ecs`, `ReflectMapEntities::map_entites` now requires an
additional `entities` parameter to specify which entities it applies to.
To keep the old behavior, use the new
`ReflectMapEntities::map_all_entities`, but consider if passing the
entities in specifically might be better for your use case to avoid
bugs.

crates/bevy_ecs/src/reflect.rs

@@ -412,8 +412,8 @@ impl_from_reflect_value!(Entity);
 
 #[derive(Clone)]
 pub struct ReflectMapEntities {
-    map_entities: fn(&mut World, &mut EntityMapper),
-    map_specific_entities: fn(&mut World, &mut EntityMapper, &[Entity]),
+    map_all_entities: fn(&mut World, &mut EntityMapper),
+    map_entities: fn(&mut World, &mut EntityMapper, &[Entity]),
 }
 
 impl ReflectMapEntities {
@@ -424,25 +424,21 @@ impl ReflectMapEntities {
     /// by the [`EntityMap`] might already contain valid entity references, you should use [`map_entities`](Self::map_entities).
     ///
     /// An example of this: A scene can be loaded with `Parent` components, but then a `Parent` component can be added
-    /// to these entities after they have been loaded. If you reload the scene using [`map_entities`](Self::map_entities), those `Parent`
+    /// to these entities after they have been loaded. If you reload the scene using [`map_all_entities`](Self::map_all_entities), those `Parent`
     /// components with already valid entity references could be updated to point at something else entirely.
-    pub fn map_entities(&self, world: &mut World, entity_map: &mut EntityMap) {
-        entity_map.world_scope(world, self.map_entities);
+    pub fn map_all_entities(&self, world: &mut World, entity_map: &mut EntityMap) {
+        entity_map.world_scope(world, self.map_all_entities);
     }
 
-    /// This is like [`map_entities`](Self::map_entities), but only applied to specific entities, not all values
+    /// A general method for applying [`MapEntities`] behavior to elements in an [`EntityMap`]. Unlike
+    /// [`map_all_entities`](Self::map_all_entities), this is applied to specific entities, not all values
     /// in the [`EntityMap`].
     ///
     /// This is useful mostly for when you need to be careful not to update components that already contain valid entity
-    /// values. See [`map_entities`](Self::map_entities) for more details.
-    pub fn map_specific_entities(
-        &self,
-        world: &mut World,
-        entity_map: &mut EntityMap,
-        entities: &[Entity],
-    ) {
+    /// values. See [`map_all_entities`](Self::map_all_entities) for more details.
+    pub fn map_entities(&self, world: &mut World, entity_map: &mut EntityMap, entities: &[Entity]) {
         entity_map.world_scope(world, |world, mapper| {
-            (self.map_specific_entities)(world, mapper, entities);
+            (self.map_entities)(world, mapper, entities);
         });
     }
 }
@@ -450,14 +446,14 @@ impl ReflectMapEntities {
 impl<C: Component + MapEntities> FromType<C> for ReflectMapEntities {
     fn from_type() -> Self {
         ReflectMapEntities {
-            map_specific_entities: |world, entity_mapper, entities| {
+            map_entities: |world, entity_mapper, entities| {
                 for &entity in entities {
                     if let Some(mut component) = world.get_mut::<C>(entity) {
                         component.map_entities(entity_mapper);
                     }
                 }
             },
-            map_entities: |world, entity_mapper| {
+            map_all_entities: |world, entity_mapper| {
                 let entities = entity_mapper.get_map().values().collect::<Vec<Entity>>();
                 for entity in &entities {
                     if let Some(mut component) = world.get_mut::<C>(*entity) {

crates/bevy_scene/src/dynamic_scene.rs

@@ -142,7 +142,7 @@ impl DynamicScene {
                 "we should be getting TypeId from this TypeRegistration in the first place",
             );
             if let Some(map_entities_reflect) = registration.data::<ReflectMapEntities>() {
-                map_entities_reflect.map_specific_entities(world, entity_map, &entities);
+                map_entities_reflect.map_entities(world, entity_map, &entities);
             }
         }
 

crates/bevy_scene/src/scene.rs

@@ -120,7 +120,7 @@ impl Scene {
 
         for registration in type_registry.iter() {
             if let Some(map_entities_reflect) = registration.data::<ReflectMapEntities>() {
-                map_entities_reflect.map_entities(world, &mut instance_info.entity_map);
+                map_entities_reflect.map_all_entities(world, &mut instance_info.entity_map);
             }
         }